1 /* $OpenBSD: session.c,v 1.280 2016/02/16 03:37:48 djm Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 #include <sys/types.h>
40 #include <sys/param.h>
41 #ifdef HAVE_SYS_STAT_H
42 # include <sys/stat.h>
44 #include <sys/socket.h>
48 #include <arpa/inet.h>
67 #include "openbsd-compat/sys-queue.h"
86 #include "auth-options.h"
88 #include "pathnames.h"
93 #include "serverloop.h"
97 #include "monitor_wrap.h"
100 #if defined(KRB5) && defined(USE_AFS)
105 #include <selinux/selinux.h>
108 #define IS_INTERNAL_SFTP(c) \
109 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
110 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
111 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
112 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
116 Session *session_new(void);
117 void session_set_fds(Session *, int, int, int, int, int);
118 void session_pty_cleanup(Session *);
119 void session_proctitle(Session *);
120 int session_setup_x11fwd(Session *);
121 int do_exec_pty(Session *, const char *);
122 int do_exec_no_pty(Session *, const char *);
123 int do_exec(Session *, const char *);
124 void do_login(Session *, const char *);
125 #ifdef LOGIN_NEEDS_UTMPX
126 static void do_pre_login(Session *s);
128 void do_child(Session *, const char *);
130 int check_quietlogin(Session *, const char *);
132 static void do_authenticated1(Authctxt *);
133 static void do_authenticated2(Authctxt *);
135 static int session_pty_req(Session *);
138 extern ServerOptions options;
139 extern char *__progname;
140 extern int log_stderr;
141 extern int debug_flag;
142 extern u_int utmp_len;
143 extern int startup_pipe;
144 extern void destroy_sensitive_data(void);
145 extern Buffer loginmsg;
147 /* original command from peer. */
148 const char *original_command = NULL;
151 static int sessions_first_unused = -1;
152 static int sessions_nalloc = 0;
153 static Session *sessions = NULL;
155 #define SUBSYSTEM_NONE 0
156 #define SUBSYSTEM_EXT 1
157 #define SUBSYSTEM_INT_SFTP 2
158 #define SUBSYSTEM_INT_SFTP_ERROR 3
160 #ifdef HAVE_LOGIN_CAP
164 static int is_child = 0;
165 static int in_chroot = 0;
167 /* Name and directory of socket for authentication agent forwarding. */
168 static char *auth_sock_name = NULL;
169 static char *auth_sock_dir = NULL;
171 /* removes the agent forwarding socket */
174 auth_sock_cleanup_proc(struct passwd *pw)
176 if (auth_sock_name != NULL) {
177 temporarily_use_uid(pw);
178 unlink(auth_sock_name);
179 rmdir(auth_sock_dir);
180 auth_sock_name = NULL;
186 auth_input_request_forwarding(struct passwd * pw)
191 if (auth_sock_name != NULL) {
192 error("authentication forwarding requested twice.");
196 /* Temporarily drop privileged uid for mkdir/bind. */
197 temporarily_use_uid(pw);
199 /* Allocate a buffer for the socket name, and format the name. */
200 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
202 /* Create private directory for socket */
203 if (mkdtemp(auth_sock_dir) == NULL) {
204 packet_send_debug("Agent forwarding disabled: "
205 "mkdtemp() failed: %.100s", strerror(errno));
208 auth_sock_dir = NULL;
212 xasprintf(&auth_sock_name, "%s/agent.%ld",
213 auth_sock_dir, (long) getpid());
215 /* Start a Unix listener on auth_sock_name. */
216 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0);
218 /* Restore the privileged uid. */
221 /* Check for socket/bind/listen failure. */
225 /* Allocate a channel for the authentication agent socket. */
226 nc = channel_new("auth socket",
227 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
228 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
229 0, "auth socket", 1);
230 nc->path = xstrdup(auth_sock_name);
234 free(auth_sock_name);
235 if (auth_sock_dir != NULL) {
236 rmdir(auth_sock_dir);
241 auth_sock_name = NULL;
242 auth_sock_dir = NULL;
247 display_loginmsg(void)
249 if (buffer_len(&loginmsg) > 0) {
250 buffer_append(&loginmsg, "\0", 1);
251 printf("%s", (char *)buffer_ptr(&loginmsg));
252 buffer_clear(&loginmsg);
257 do_authenticated(Authctxt *authctxt)
259 setproctitle("%s", authctxt->pw->pw_name);
261 /* setup the channel layer */
262 /* XXX - streamlocal? */
263 if (no_port_forwarding_flag ||
264 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
265 channel_disable_adm_local_opens();
267 channel_permit_all_opens();
272 do_authenticated2(authctxt);
274 do_authenticated1(authctxt);
276 do_cleanup(authctxt);
279 /* Check untrusted xauth strings for metacharacters */
281 xauth_valid_string(const char *s)
285 for (i = 0; s[i] != '\0'; i++) {
286 if (!isalnum((u_char)s[i]) &&
287 s[i] != '.' && s[i] != ':' && s[i] != '/' &&
288 s[i] != '-' && s[i] != '_')
295 * Prepares for an interactive session. This is called after the user has
296 * been successfully authenticated. During this message exchange, pseudo
297 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
298 * are requested, etc.
301 do_authenticated1(Authctxt *authctxt)
305 int success, type, screen_flag;
306 int enable_compression_after_reply = 0;
307 u_int proto_len, data_len, dlen, compression_level = 0;
311 error("no more sessions");
314 s->authctxt = authctxt;
315 s->pw = authctxt->pw;
318 * We stay in this loop until the client requests to execute a shell
324 /* Get a packet from the client. */
325 type = packet_read();
327 /* Process the packet. */
329 case SSH_CMSG_REQUEST_COMPRESSION:
330 compression_level = packet_get_int();
332 if (compression_level < 1 || compression_level > 9) {
333 packet_send_debug("Received invalid compression level %d.",
337 if (options.compression == COMP_NONE) {
338 debug2("compression disabled");
341 /* Enable compression after we have responded with SUCCESS. */
342 enable_compression_after_reply = 1;
346 case SSH_CMSG_REQUEST_PTY:
347 success = session_pty_req(s);
350 case SSH_CMSG_X11_REQUEST_FORWARDING:
351 s->auth_proto = packet_get_string(&proto_len);
352 s->auth_data = packet_get_string(&data_len);
354 screen_flag = packet_get_protocol_flags() &
355 SSH_PROTOFLAG_SCREEN_NUMBER;
356 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
358 if (packet_remaining() == 4) {
360 debug2("Buggy client: "
361 "X11 screen flag missing");
362 s->screen = packet_get_int();
367 if (xauth_valid_string(s->auth_proto) &&
368 xauth_valid_string(s->auth_data))
369 success = session_setup_x11fwd(s);
372 error("Invalid X11 forwarding data");
377 s->auth_proto = NULL;
382 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
383 if (!options.allow_agent_forwarding ||
384 no_agent_forwarding_flag || compat13) {
385 debug("Authentication agent forwarding not permitted for this authentication.");
388 debug("Received authentication agent forwarding request.");
389 success = auth_input_request_forwarding(s->pw);
392 case SSH_CMSG_PORT_FORWARD_REQUEST:
393 if (no_port_forwarding_flag) {
394 debug("Port forwarding not permitted for this authentication.");
397 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
398 debug("Port forwarding not permitted.");
401 debug("Received TCP/IP port forwarding request.");
402 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
403 &options.fwd_opts) < 0) {
404 debug("Port forwarding failed.");
410 case SSH_CMSG_MAX_PACKET_SIZE:
411 if (packet_set_maxsize(packet_get_int()) > 0)
415 case SSH_CMSG_EXEC_SHELL:
416 case SSH_CMSG_EXEC_CMD:
417 if (type == SSH_CMSG_EXEC_CMD) {
418 command = packet_get_string(&dlen);
419 debug("Exec command '%.500s'", command);
420 if (do_exec(s, command) != 0)
422 "command execution failed");
425 if (do_exec(s, NULL) != 0)
427 "shell execution failed");
435 * Any unknown messages in this phase are ignored,
436 * and a failure message is returned.
438 logit("Unknown packet type received after authentication: %d", type);
440 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
444 /* Enable compression now that we have replied if appropriate. */
445 if (enable_compression_after_reply) {
446 enable_compression_after_reply = 0;
447 packet_start_compression(compression_level);
454 * This is called to fork and execute a command when we have no tty. This
455 * will call do_child from the child, and server_loop from the parent after
456 * setting up file descriptors and such.
459 do_exec_no_pty(Session *s, const char *command)
464 int pin[2], pout[2], perr[2];
467 fatal("do_exec_no_pty: no session");
469 /* Allocate pipes for communicating with the program. */
471 error("%s: pipe in: %.100s", __func__, strerror(errno));
474 if (pipe(pout) < 0) {
475 error("%s: pipe out: %.100s", __func__, strerror(errno));
480 if (pipe(perr) < 0) {
481 error("%s: pipe err: %.100s", __func__,
490 int inout[2], err[2];
493 fatal("do_exec_no_pty: no session");
495 /* Uses socket pairs to communicate with the program. */
496 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
497 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
500 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
501 error("%s: socketpair #2: %.100s", __func__,
509 session_proctitle(s);
511 /* Fork the child. */
512 switch ((pid = fork())) {
514 error("%s: fork: %.100s", __func__, strerror(errno));
532 /* Child. Reinitialize the log since the pid has changed. */
533 log_init(__progname, options.log_level,
534 options.log_facility, log_stderr);
537 * Create a new session and process group since the 4.4BSD
538 * setlogin() affects the entire process group.
541 error("setsid failed: %.100s", strerror(errno));
545 * Redirect stdin. We close the parent side of the socket
546 * pair, and make the child side the standard input.
549 if (dup2(pin[0], 0) < 0)
550 perror("dup2 stdin");
553 /* Redirect stdout. */
555 if (dup2(pout[1], 1) < 0)
556 perror("dup2 stdout");
559 /* Redirect stderr. */
561 if (dup2(perr[1], 2) < 0)
562 perror("dup2 stderr");
566 * Redirect stdin, stdout, and stderr. Stdin and stdout will
567 * use the same socket, as some programs (particularly rdist)
568 * seem to depend on it.
572 if (dup2(inout[0], 0) < 0) /* stdin */
573 perror("dup2 stdin");
574 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
575 perror("dup2 stdout");
577 if (dup2(err[0], 2) < 0) /* stderr */
578 perror("dup2 stderr");
584 cray_init_job(s->pw); /* set up cray jid and tmpdir */
587 /* Do processing for the child (exec command etc). */
588 do_child(s, command);
595 signal(WJSIGNAL, cray_job_termination_handler);
598 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
602 /* Set interactive/non-interactive mode. */
603 packet_set_interactive(s->display != NULL,
604 options.ip_qos_interactive, options.ip_qos_bulk);
607 * Clear loginmsg, since it's the child's responsibility to display
608 * it to the user, otherwise multiple sessions may accumulate
609 * multiple copies of the login messages.
611 buffer_clear(&loginmsg);
614 /* We are the parent. Close the child sides of the pipes. */
620 session_set_fds(s, pin[1], pout[0], perr[0],
623 /* Enter the interactive session. */
624 server_loop(pid, pin[1], pout[0], perr[0]);
625 /* server_loop has closed pin[1], pout[0], and perr[0]. */
628 /* We are the parent. Close the child sides of the socket pairs. */
633 * Enter the interactive session. Note: server_loop must be able to
634 * handle the case that fdin and fdout are the same.
637 session_set_fds(s, inout[1], inout[1], err[1],
640 server_loop(pid, inout[1], inout[1], err[1]);
641 /* server_loop has closed inout[1] and err[1]. */
648 * This is called to fork and execute a command when we have a tty. This
649 * will call do_child from the child, and server_loop from the parent after
650 * setting up file descriptors, controlling tty, updating wtmp, utmp,
651 * lastlog, and other such operations.
654 do_exec_pty(Session *s, const char *command)
656 int fdout, ptyfd, ttyfd, ptymaster;
660 fatal("do_exec_pty: no session");
665 * Create another descriptor of the pty master side for use as the
666 * standard input. We could use the original descriptor, but this
667 * simplifies code in server_loop. The descriptor is bidirectional.
668 * Do this before forking (and cleanup in the child) so as to
669 * detect and gracefully fail out-of-fd conditions.
671 if ((fdout = dup(ptyfd)) < 0) {
672 error("%s: dup #1: %s", __func__, strerror(errno));
677 /* we keep a reference to the pty master */
678 if ((ptymaster = dup(ptyfd)) < 0) {
679 error("%s: dup #2: %s", __func__, strerror(errno));
686 /* Fork the child. */
687 switch ((pid = fork())) {
689 error("%s: fork: %.100s", __func__, strerror(errno));
701 /* Child. Reinitialize the log because the pid has changed. */
702 log_init(__progname, options.log_level,
703 options.log_facility, log_stderr);
704 /* Close the master side of the pseudo tty. */
707 /* Make the pseudo tty our controlling tty. */
708 pty_make_controlling_tty(&ttyfd, s->tty);
710 /* Redirect stdin/stdout/stderr from the pseudo tty. */
711 if (dup2(ttyfd, 0) < 0)
712 error("dup2 stdin: %s", strerror(errno));
713 if (dup2(ttyfd, 1) < 0)
714 error("dup2 stdout: %s", strerror(errno));
715 if (dup2(ttyfd, 2) < 0)
716 error("dup2 stderr: %s", strerror(errno));
718 /* Close the extra descriptor for the pseudo tty. */
721 /* record login, etc. similar to login(1) */
723 if (!(options.use_login && command == NULL)) {
725 cray_init_job(s->pw); /* set up cray jid and tmpdir */
727 do_login(s, command);
729 # ifdef LOGIN_NEEDS_UTMPX
735 * Do common processing for the child, such as execing
738 do_child(s, command);
745 signal(WJSIGNAL, cray_job_termination_handler);
748 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
753 /* Parent. Close the slave side of the pseudo tty. */
756 /* Enter interactive session. */
757 s->ptymaster = ptymaster;
758 packet_set_interactive(1,
759 options.ip_qos_interactive, options.ip_qos_bulk);
761 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
763 server_loop(pid, ptyfd, fdout, -1);
764 /* server_loop _has_ closed ptyfd and fdout. */
769 #ifdef LOGIN_NEEDS_UTMPX
771 do_pre_login(Session *s)
774 struct sockaddr_storage from;
775 pid_t pid = getpid();
778 * Get IP address of client. If the connection is not a socket, let
779 * the address be 0.0.0.0.
781 memset(&from, 0, sizeof(from));
782 fromlen = sizeof(from);
783 if (packet_connection_is_on_socket()) {
784 if (getpeername(packet_get_connection_in(),
785 (struct sockaddr *)&from, &fromlen) < 0) {
786 debug("getpeername: %.100s", strerror(errno));
791 record_utmp_only(pid, s->tty, s->pw->pw_name,
792 get_remote_name_or_ip(utmp_len, options.use_dns),
793 (struct sockaddr *)&from, fromlen);
798 * This is called to fork and execute a command. If another command is
799 * to be forced, execute that instead.
802 do_exec(Session *s, const char *command)
805 const char *forced = NULL, *tty = NULL;
806 char session_type[1024];
808 if (options.adm_forced_command) {
809 original_command = command;
810 command = options.adm_forced_command;
812 } else if (forced_command) {
813 original_command = command;
814 command = forced_command;
815 forced = "(key-option)";
817 if (forced != NULL) {
818 if (IS_INTERNAL_SFTP(command)) {
819 s->is_subsystem = s->is_subsystem ?
820 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
821 } else if (s->is_subsystem)
822 s->is_subsystem = SUBSYSTEM_EXT;
823 snprintf(session_type, sizeof(session_type),
824 "forced-command %s '%.900s'", forced, command);
825 } else if (s->is_subsystem) {
826 snprintf(session_type, sizeof(session_type),
827 "subsystem '%.900s'", s->subsys);
828 } else if (command == NULL) {
829 snprintf(session_type, sizeof(session_type), "shell");
831 /* NB. we don't log unforced commands to preserve privacy */
832 snprintf(session_type, sizeof(session_type), "command");
835 if (s->ttyfd != -1) {
837 if (strncmp(tty, "/dev/", 5) == 0)
841 verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
843 tty == NULL ? "" : " on ",
844 tty == NULL ? "" : tty,
850 #ifdef SSH_AUDIT_EVENTS
852 PRIVSEP(audit_run_command(command));
853 else if (s->ttyfd == -1) {
854 char *shell = s->pw->pw_shell;
856 if (shell[0] == '\0') /* empty shell means /bin/sh */
858 PRIVSEP(audit_run_command(shell));
862 ret = do_exec_pty(s, command);
864 ret = do_exec_no_pty(s, command);
866 original_command = NULL;
869 * Clear loginmsg: it's the child's responsibility to display
870 * it to the user, otherwise multiple sessions may accumulate
871 * multiple copies of the login messages.
873 buffer_clear(&loginmsg);
878 /* administrative, login(1)-like work */
880 do_login(Session *s, const char *command)
883 struct sockaddr_storage from;
884 struct passwd * pw = s->pw;
885 pid_t pid = getpid();
888 * Get IP address of client. If the connection is not a socket, let
889 * the address be 0.0.0.0.
891 memset(&from, 0, sizeof(from));
892 fromlen = sizeof(from);
893 if (packet_connection_is_on_socket()) {
894 if (getpeername(packet_get_connection_in(),
895 (struct sockaddr *)&from, &fromlen) < 0) {
896 debug("getpeername: %.100s", strerror(errno));
901 /* Record that there was a login on that tty from the remote host. */
903 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
904 get_remote_name_or_ip(utmp_len,
906 (struct sockaddr *)&from, fromlen);
910 * If password change is needed, do it now.
911 * This needs to occur before the ~/.hushlogin check.
913 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
916 s->authctxt->force_pwchange = 0;
917 /* XXX - signal [net] parent to enable forwardings */
921 if (check_quietlogin(s, command))
930 * Display the message of the day.
938 if (options.print_motd) {
939 #ifdef HAVE_LOGIN_CAP
940 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
943 f = fopen("/etc/motd", "r");
946 while (fgets(buf, sizeof(buf), f))
955 * Check for quiet login, either .hushlogin or command given.
958 check_quietlogin(Session *s, const char *command)
961 struct passwd *pw = s->pw;
964 /* Return 1 if .hushlogin exists or a command given. */
967 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
968 #ifdef HAVE_LOGIN_CAP
969 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
972 if (stat(buf, &st) >= 0)
979 * Sets the value of the given variable in the environment. If the variable
980 * already exists, its value is overridden.
983 child_set_env(char ***envp, u_int *envsizep, const char *name,
990 if (strchr(name, '=') != NULL) {
991 error("Invalid environment variable \"%.100s\"", name);
996 * If we're passed an uninitialized list, allocate a single null
997 * entry before continuing.
999 if (*envp == NULL && *envsizep == 0) {
1000 *envp = xmalloc(sizeof(char *));
1006 * Find the slot where the value should be stored. If the variable
1007 * already exists, we reuse the slot; otherwise we append a new slot
1008 * at the end of the array, expanding if necessary.
1011 namelen = strlen(name);
1012 for (i = 0; env[i]; i++)
1013 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1016 /* Reuse the slot. */
1019 /* New variable. Expand if necessary. */
1020 envsize = *envsizep;
1021 if (i >= envsize - 1) {
1022 if (envsize >= 1000)
1023 fatal("child_set_env: too many env vars");
1025 env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1026 *envsizep = envsize;
1028 /* Need to set the NULL pointer at end of array beyond the new slot. */
1032 /* Allocate space and format the variable in the appropriate slot. */
1033 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1034 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1038 * Reads environment variables from the given file and adds/overrides them
1039 * into the environment. If the file does not exist, this does nothing.
1040 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1041 * and assignments of the form name=value. No other forms are allowed.
1044 read_environment_file(char ***env, u_int *envsize,
1045 const char *filename)
1052 f = fopen(filename, "r");
1056 while (fgets(buf, sizeof(buf), f)) {
1057 if (++lineno > 1000)
1058 fatal("Too many lines in environment file %s", filename);
1059 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1061 if (!*cp || *cp == '#' || *cp == '\n')
1064 cp[strcspn(cp, "\n")] = '\0';
1066 value = strchr(cp, '=');
1067 if (value == NULL) {
1068 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1073 * Replace the equals sign by nul, and advance value to
1078 child_set_env(env, envsize, cp, value);
1083 #ifdef HAVE_ETC_DEFAULT_LOGIN
1085 * Return named variable from specified environment, or NULL if not present.
1088 child_get_env(char **env, const char *name)
1094 for (i=0; env[i] != NULL; i++)
1095 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1096 return(env[i] + len + 1);
1101 * Read /etc/default/login.
1102 * We pick up the PATH (or SUPATH for root) and UMASK.
1105 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1107 char **tmpenv = NULL, *var;
1108 u_int i, tmpenvsize = 0;
1112 * We don't want to copy the whole file to the child's environment,
1113 * so we use a temporary environment and copy the variables we're
1116 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1122 var = child_get_env(tmpenv, "SUPATH");
1124 var = child_get_env(tmpenv, "PATH");
1126 child_set_env(env, envsize, "PATH", var);
1128 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1129 if (sscanf(var, "%5lo", &mask) == 1)
1130 umask((mode_t)mask);
1132 for (i = 0; tmpenv[i] != NULL; i++)
1136 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1139 copy_environment(char **source, char ***env, u_int *envsize)
1141 char *var_name, *var_val;
1147 for(i = 0; source[i] != NULL; i++) {
1148 var_name = xstrdup(source[i]);
1149 if ((var_val = strstr(var_name, "=")) == NULL) {
1155 debug3("Copy environment: %s=%s", var_name, var_val);
1156 child_set_env(env, envsize, var_name, var_val);
1163 do_setup_env(Session *s, const char *shell)
1168 struct passwd *pw = s->pw;
1169 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1172 extern char **environ;
1176 /* Initialize the environment. */
1178 env = xcalloc(envsize, sizeof(char *));
1183 * The Windows environment contains some setting which are
1184 * important for a running system. They must not be dropped.
1189 p = fetch_windows_environment();
1190 copy_environment(p, &env, &envsize);
1191 free_windows_environment(p);
1196 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1199 /* Allow any GSSAPI methods that we've used to alter
1200 * the childs environment as they see fit
1202 ssh_gssapi_do_child(&env, &envsize);
1205 if (!options.use_login) {
1206 /* Set basic environment. */
1207 for (i = 0; i < s->num_env; i++)
1208 child_set_env(&env, &envsize, s->env[i].name,
1211 child_set_env(&env, &envsize, "USER", pw->pw_name);
1212 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1214 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1216 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1217 snprintf(buf, sizeof buf, "%.200s/%.50s",
1218 _PATH_MAILDIR, pw->pw_name);
1219 child_set_env(&env, &envsize, "MAIL", buf);
1220 #ifdef HAVE_LOGIN_CAP
1221 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1222 child_set_env(&env, &envsize, "TERM", "su");
1224 environ = xmalloc(sizeof(char *));
1226 (void) setusercontext(lc, pw, pw->pw_uid,
1227 LOGIN_SETENV|LOGIN_SETPATH);
1228 copy_environment(environ, &env, &envsize);
1229 for (var = environ; *var != NULL; ++var)
1233 #else /* HAVE_LOGIN_CAP */
1234 # ifndef HAVE_CYGWIN
1236 * There's no standard path on Windows. The path contains
1237 * important components pointing to the system directories,
1238 * needed for loading shared libraries. So the path better
1239 * remains intact here.
1241 # ifdef HAVE_ETC_DEFAULT_LOGIN
1242 read_etc_default_login(&env, &envsize, pw->pw_uid);
1243 path = child_get_env(env, "PATH");
1244 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1245 if (path == NULL || *path == '\0') {
1246 child_set_env(&env, &envsize, "PATH",
1247 s->pw->pw_uid == 0 ?
1248 SUPERUSER_PATH : _PATH_STDPATH);
1250 # endif /* HAVE_CYGWIN */
1251 #endif /* HAVE_LOGIN_CAP */
1253 /* Normal systems set SHELL by default. */
1254 child_set_env(&env, &envsize, "SHELL", shell);
1257 /* Set custom environment options from RSA authentication. */
1258 if (!options.use_login) {
1259 while (custom_environment) {
1260 struct envstring *ce = custom_environment;
1263 for (i = 0; str[i] != '=' && str[i]; i++)
1265 if (str[i] == '=') {
1267 child_set_env(&env, &envsize, str, str + i + 1);
1269 custom_environment = ce->next;
1275 /* SSH_CLIENT deprecated */
1276 snprintf(buf, sizeof buf, "%.50s %d %d",
1277 get_remote_ipaddr(), get_remote_port(), get_local_port());
1278 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1280 laddr = get_local_ipaddr(packet_get_connection_in());
1281 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1282 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1284 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1287 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1289 child_set_env(&env, &envsize, "TERM", s->term);
1291 child_set_env(&env, &envsize, "DISPLAY", s->display);
1292 if (original_command)
1293 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1297 if (cray_tmpdir[0] != '\0')
1298 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1299 #endif /* _UNICOS */
1302 * Since we clear KRB5CCNAME at startup, if it's set now then it
1303 * must have been set by a native authentication method (eg AIX or
1304 * SIA), so copy it to the child.
1309 if ((cp = getenv("KRB5CCNAME")) != NULL)
1310 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1317 if ((cp = getenv("AUTHSTATE")) != NULL)
1318 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1319 read_environment_file(&env, &envsize, "/etc/environment");
1323 if (s->authctxt->krb5_ccname)
1324 child_set_env(&env, &envsize, "KRB5CCNAME",
1325 s->authctxt->krb5_ccname);
1329 * Pull in any environment variables that may have
1332 if (options.use_pam) {
1335 p = fetch_pam_child_environment();
1336 copy_environment(p, &env, &envsize);
1337 free_pam_environment(p);
1339 p = fetch_pam_environment();
1340 copy_environment(p, &env, &envsize);
1341 free_pam_environment(p);
1343 #endif /* USE_PAM */
1345 if (auth_sock_name != NULL)
1346 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1349 /* read $HOME/.ssh/environment. */
1350 if (options.permit_user_env && !options.use_login) {
1351 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1352 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1353 read_environment_file(&env, &envsize, buf);
1356 /* dump the environment */
1357 fprintf(stderr, "Environment:\n");
1358 for (i = 0; env[i]; i++)
1359 fprintf(stderr, " %.200s\n", env[i]);
1365 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1366 * first in this order).
1369 do_rc_files(Session *s, const char *shell)
1377 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1379 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1380 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1381 !no_user_rc && options.permit_user_rc &&
1382 stat(_PATH_SSH_USER_RC, &st) >= 0) {
1383 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1384 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1386 fprintf(stderr, "Running %s\n", cmd);
1387 f = popen(cmd, "w");
1390 fprintf(f, "%s %s\n", s->auth_proto,
1394 fprintf(stderr, "Could not run %s\n",
1396 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1398 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1399 _PATH_SSH_SYSTEM_RC);
1400 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1403 fprintf(f, "%s %s\n", s->auth_proto,
1407 fprintf(stderr, "Could not run %s\n",
1408 _PATH_SSH_SYSTEM_RC);
1409 } else if (do_xauth && options.xauth_location != NULL) {
1410 /* Add authority data to .Xauthority if appropriate. */
1413 "Running %.500s remove %.100s\n",
1414 options.xauth_location, s->auth_display);
1416 "%.500s add %.100s %.100s %.100s\n",
1417 options.xauth_location, s->auth_display,
1418 s->auth_proto, s->auth_data);
1420 snprintf(cmd, sizeof cmd, "%s -q -",
1421 options.xauth_location);
1422 f = popen(cmd, "w");
1424 fprintf(f, "remove %s\n",
1426 fprintf(f, "add %s %s %s\n",
1427 s->auth_display, s->auth_proto,
1431 fprintf(stderr, "Could not run %s\n",
1438 do_nologin(struct passwd *pw)
1441 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1444 #ifdef HAVE_LOGIN_CAP
1445 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1447 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1449 if (pw->pw_uid == 0)
1453 if (stat(nl, &sb) == -1) {
1459 /* /etc/nologin exists. Print its contents if we can and exit. */
1460 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1461 if ((f = fopen(nl, "r")) != NULL) {
1462 while (fgets(buf, sizeof(buf), f))
1470 * Chroot into a directory after checking it for safety: all path components
1471 * must be root-owned directories with strict permissions.
1474 safely_chroot(const char *path, uid_t uid)
1477 char component[PATH_MAX];
1481 fatal("chroot path does not begin at root");
1482 if (strlen(path) >= sizeof(component))
1483 fatal("chroot path too long");
1486 * Descend the path, checking that each component is a
1487 * root-owned directory with strict permissions.
1489 for (cp = path; cp != NULL;) {
1490 if ((cp = strchr(cp, '/')) == NULL)
1491 strlcpy(component, path, sizeof(component));
1494 memcpy(component, path, cp - path);
1495 component[cp - path] = '\0';
1498 debug3("%s: checking '%s'", __func__, component);
1500 if (stat(component, &st) != 0)
1501 fatal("%s: stat(\"%s\"): %s", __func__,
1502 component, strerror(errno));
1503 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1504 fatal("bad ownership or modes for chroot "
1505 "directory %s\"%s\"",
1506 cp == NULL ? "" : "component ", component);
1507 if (!S_ISDIR(st.st_mode))
1508 fatal("chroot path %s\"%s\" is not a directory",
1509 cp == NULL ? "" : "component ", component);
1513 if (chdir(path) == -1)
1514 fatal("Unable to chdir to chroot path \"%s\": "
1515 "%s", path, strerror(errno));
1516 if (chroot(path) == -1)
1517 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1518 if (chdir("/") == -1)
1519 fatal("%s: chdir(/) after chroot: %s",
1520 __func__, strerror(errno));
1521 verbose("Changed root directory to \"%s\"", path);
1524 /* Set login name, uid, gid, and groups. */
1526 do_setusercontext(struct passwd *pw)
1528 char *chroot_path, *tmp;
1530 platform_setusercontext(pw);
1532 if (platform_privileged_uidswap()) {
1533 #ifdef HAVE_LOGIN_CAP
1534 if (setusercontext(lc, pw, pw->pw_uid,
1535 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1536 perror("unable to set user context");
1540 if (setlogin(pw->pw_name) < 0)
1541 error("setlogin failed: %s", strerror(errno));
1542 if (setgid(pw->pw_gid) < 0) {
1546 /* Initialize the group list. */
1547 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1548 perror("initgroups");
1554 platform_setusercontext_post_groups(pw);
1556 if (!in_chroot && options.chroot_directory != NULL &&
1557 strcasecmp(options.chroot_directory, "none") != 0) {
1558 tmp = tilde_expand_filename(options.chroot_directory,
1560 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1561 "u", pw->pw_name, (char *)NULL);
1562 safely_chroot(chroot_path, pw->pw_uid);
1565 /* Make sure we don't attempt to chroot again */
1566 free(options.chroot_directory);
1567 options.chroot_directory = NULL;
1571 #ifdef HAVE_LOGIN_CAP
1572 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1573 perror("unable to set user context (setuser)");
1577 * FreeBSD's setusercontext() will not apply the user's
1578 * own umask setting unless running with the user's UID.
1580 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1584 * In a chroot environment, the set_id() will always fail;
1585 * typically because of the lack of necessary authentication
1586 * services and runtime such as ./usr/lib/libiaf.so,
1587 * ./usr/lib/libpam.so.1, and ./etc/passwd We skip it in the
1588 * internal sftp chroot case. We'll lose auditing and ACLs but
1589 * permanently_set_uid will take care of the rest.
1591 if (!in_chroot && set_id(pw->pw_name) != 0)
1592 fatal("set_id(%s) Failed", pw->pw_name);
1593 # endif /* USE_LIBIAF */
1594 /* Permanently switch to the desired uid. */
1595 permanently_set_uid(pw);
1597 } else if (options.chroot_directory != NULL &&
1598 strcasecmp(options.chroot_directory, "none") != 0) {
1599 fatal("server lacks privileges to chroot to ChrootDirectory");
1602 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1603 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1607 do_pwchange(Session *s)
1610 fprintf(stderr, "WARNING: Your password has expired.\n");
1611 if (s->ttyfd != -1) {
1613 "You must change your password now and login again!\n");
1617 #ifdef PASSWD_NEEDS_USERNAME
1618 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1621 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1626 "Password change required but no TTY available.\n");
1632 launch_login(struct passwd *pw, const char *hostname)
1634 /* Launch login(1). */
1636 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1637 #ifdef xxxLOGIN_NEEDS_TERM
1638 (s->term ? s->term : "unknown"),
1639 #endif /* LOGIN_NEEDS_TERM */
1640 #ifdef LOGIN_NO_ENDOPT
1641 "-p", "-f", pw->pw_name, (char *)NULL);
1643 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1646 /* Login couldn't be executed, die. */
1653 child_close_fds(void)
1655 extern int auth_sock;
1657 if (auth_sock != -1) {
1662 if (packet_get_connection_in() == packet_get_connection_out())
1663 close(packet_get_connection_in());
1665 close(packet_get_connection_in());
1666 close(packet_get_connection_out());
1669 * Close all descriptors related to channels. They will still remain
1670 * open in the parent.
1672 /* XXX better use close-on-exec? -markus */
1673 channel_close_all();
1676 * Close any extra file descriptors. Note that there may still be
1677 * descriptors left by system functions. They will be closed later.
1682 * Close any extra open file descriptors so that we don't have them
1683 * hanging around in clients. Note that we want to do this after
1684 * initgroups, because at least on Solaris 2.3 it leaves file
1687 closefrom(STDERR_FILENO + 1);
1691 * Performs common processing for the child, such as setting up the
1692 * environment, closing extra file descriptors, setting the user and group
1693 * ids, and executing the command or shell.
1697 do_child(Session *s, const char *command)
1699 extern char **environ;
1701 char *argv[ARGV_MAX];
1702 const char *shell, *shell0, *hostname = NULL;
1703 struct passwd *pw = s->pw;
1706 /* remove hostkey from the child's memory */
1707 destroy_sensitive_data();
1709 /* Force a password change */
1710 if (s->authctxt->force_pwchange) {
1711 do_setusercontext(pw);
1717 /* login(1) is only called if we execute the login shell */
1718 if (options.use_login && command != NULL)
1719 options.use_login = 0;
1722 cray_setup(pw->pw_uid, pw->pw_name, command);
1723 #endif /* _UNICOS */
1726 * Login(1) does this as well, and it needs uid 0 for the "-h"
1727 * switch, so we let login(1) to this for us.
1729 if (!options.use_login) {
1731 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1732 if (!check_quietlogin(s, command))
1734 #else /* HAVE_OSF_SIA */
1735 /* When PAM is enabled we rely on it to do the nologin check */
1736 if (!options.use_pam)
1738 do_setusercontext(pw);
1740 * PAM session modules in do_setusercontext may have
1741 * generated messages, so if this in an interactive
1742 * login then display them too.
1744 if (!check_quietlogin(s, command))
1746 #endif /* HAVE_OSF_SIA */
1750 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1751 debug3("PAM session not opened, exiting");
1758 * Get the shell from the password data. An empty shell field is
1759 * legal, and means /bin/sh.
1761 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1764 * Make sure $SHELL points to the shell from the password file,
1765 * even if shell is overridden from login.conf
1767 env = do_setup_env(s, shell);
1769 #ifdef HAVE_LOGIN_CAP
1770 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1773 /* we have to stash the hostname before we close our socket. */
1774 if (options.use_login)
1775 hostname = get_remote_name_or_ip(utmp_len,
1778 * Close the connection descriptors; note that this is the child, and
1779 * the server will still have the socket open, and it is important
1780 * that we do not shutdown it. Note that the descriptors cannot be
1781 * closed before building the environment, as we call
1782 * get_remote_ipaddr there.
1787 * Must take new environment into use so that .ssh/rc,
1788 * /etc/ssh/sshrc and xauth are run in the proper environment.
1792 #if defined(KRB5) && defined(USE_AFS)
1794 * At this point, we check to see if AFS is active and if we have
1795 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1796 * if we can (and need to) extend the ticket into an AFS token. If
1797 * we don't do this, we run into potential problems if the user's
1798 * home directory is in AFS and it's not world-readable.
1801 if (options.kerberos_get_afs_token && k_hasafs() &&
1802 (s->authctxt->krb5_ctx != NULL)) {
1805 debug("Getting AFS token");
1809 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1810 krb5_afslog(s->authctxt->krb5_ctx,
1811 s->authctxt->krb5_fwd_ccache, cell, NULL);
1813 krb5_afslog_home(s->authctxt->krb5_ctx,
1814 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1818 /* Change current directory to the user's home directory. */
1819 if (chdir(pw->pw_dir) < 0) {
1820 /* Suppress missing homedir warning for chroot case */
1821 #ifdef HAVE_LOGIN_CAP
1822 r = login_getcapbool(lc, "requirehome", 0);
1824 if (r || !in_chroot) {
1825 fprintf(stderr, "Could not chdir to home "
1826 "directory %s: %s\n", pw->pw_dir,
1833 closefrom(STDERR_FILENO + 1);
1835 if (!options.use_login)
1836 do_rc_files(s, shell);
1838 /* restore SIGPIPE for child */
1839 signal(SIGPIPE, SIG_DFL);
1841 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1842 printf("This service allows sftp connections only.\n");
1845 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1846 extern int optind, optreset;
1850 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1851 args = xstrdup(command ? command : "sftp-server");
1852 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1853 if (i < ARGV_MAX - 1)
1856 optind = optreset = 1;
1857 __progname = argv[0];
1859 ssh_selinux_change_context("sftpd_t");
1861 exit(sftp_server_main(i, argv, s->pw));
1866 if (options.use_login) {
1867 launch_login(pw, hostname);
1871 /* Get the last component of the shell name. */
1872 if ((shell0 = strrchr(shell, '/')) != NULL)
1878 * If we have no command, execute the shell. In this case, the shell
1879 * name to be passed in argv[0] is preceded by '-' to indicate that
1880 * this is a login shell.
1885 /* Start the shell. Set initial character to '-'. */
1888 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1889 >= sizeof(argv0) - 1) {
1895 /* Execute the shell. */
1898 execve(shell, argv, env);
1900 /* Executing the shell failed. */
1905 * Execute the command using the user's shell. This uses the -c
1906 * option to execute the command.
1908 argv[0] = (char *) shell0;
1910 argv[2] = (char *) command;
1912 execve(shell, argv, env);
1918 session_unused(int id)
1920 debug3("%s: session id %d unused", __func__, id);
1921 if (id >= options.max_sessions ||
1922 id >= sessions_nalloc) {
1923 fatal("%s: insane session id %d (max %d nalloc %d)",
1924 __func__, id, options.max_sessions, sessions_nalloc);
1926 memset(&sessions[id], 0, sizeof(*sessions));
1927 sessions[id].self = id;
1928 sessions[id].used = 0;
1929 sessions[id].chanid = -1;
1930 sessions[id].ptyfd = -1;
1931 sessions[id].ttyfd = -1;
1932 sessions[id].ptymaster = -1;
1933 sessions[id].x11_chanids = NULL;
1934 sessions[id].next_unused = sessions_first_unused;
1935 sessions_first_unused = id;
1943 if (sessions_first_unused == -1) {
1944 if (sessions_nalloc >= options.max_sessions)
1946 debug2("%s: allocate (allocated %d max %d)",
1947 __func__, sessions_nalloc, options.max_sessions);
1948 tmp = xreallocarray(sessions, sessions_nalloc + 1,
1951 error("%s: cannot allocate %d sessions",
1952 __func__, sessions_nalloc + 1);
1956 session_unused(sessions_nalloc++);
1959 if (sessions_first_unused >= sessions_nalloc ||
1960 sessions_first_unused < 0) {
1961 fatal("%s: insane first_unused %d max %d nalloc %d",
1962 __func__, sessions_first_unused, options.max_sessions,
1966 s = &sessions[sessions_first_unused];
1968 fatal("%s: session %d already used",
1969 __func__, sessions_first_unused);
1971 sessions_first_unused = s->next_unused;
1973 s->next_unused = -1;
1974 debug("session_new: session %d", s->self);
1983 for (i = 0; i < sessions_nalloc; i++) {
1984 Session *s = &sessions[i];
1986 debug("dump: used %d next_unused %d session %d %p "
1987 "channel %d pid %ld",
1998 session_open(Authctxt *authctxt, int chanid)
2000 Session *s = session_new();
2001 debug("session_open: channel %d", chanid);
2003 error("no more sessions");
2006 s->authctxt = authctxt;
2007 s->pw = authctxt->pw;
2008 if (s->pw == NULL || !authctxt->valid)
2009 fatal("no user for session %d", s->self);
2010 debug("session_open: session %d: link with channel %d", s->self, chanid);
2016 session_by_tty(char *tty)
2019 for (i = 0; i < sessions_nalloc; i++) {
2020 Session *s = &sessions[i];
2021 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2022 debug("session_by_tty: session %d tty %s", i, tty);
2026 debug("session_by_tty: unknown tty %.100s", tty);
2032 session_by_channel(int id)
2035 for (i = 0; i < sessions_nalloc; i++) {
2036 Session *s = &sessions[i];
2037 if (s->used && s->chanid == id) {
2038 debug("session_by_channel: session %d channel %d",
2043 debug("session_by_channel: unknown channel %d", id);
2049 session_by_x11_channel(int id)
2053 for (i = 0; i < sessions_nalloc; i++) {
2054 Session *s = &sessions[i];
2056 if (s->x11_chanids == NULL || !s->used)
2058 for (j = 0; s->x11_chanids[j] != -1; j++) {
2059 if (s->x11_chanids[j] == id) {
2060 debug("session_by_x11_channel: session %d "
2061 "channel %d", s->self, id);
2066 debug("session_by_x11_channel: unknown channel %d", id);
2072 session_by_pid(pid_t pid)
2075 debug("session_by_pid: pid %ld", (long)pid);
2076 for (i = 0; i < sessions_nalloc; i++) {
2077 Session *s = &sessions[i];
2078 if (s->used && s->pid == pid)
2081 error("session_by_pid: unknown pid %ld", (long)pid);
2087 session_window_change_req(Session *s)
2089 s->col = packet_get_int();
2090 s->row = packet_get_int();
2091 s->xpixel = packet_get_int();
2092 s->ypixel = packet_get_int();
2094 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2099 session_pty_req(Session *s)
2104 if (no_pty_flag || !options.permit_tty) {
2105 debug("Allocating a pty not permitted for this authentication.");
2108 if (s->ttyfd != -1) {
2109 packet_disconnect("Protocol error: you already have a pty.");
2113 s->term = packet_get_string(&len);
2116 s->col = packet_get_int();
2117 s->row = packet_get_int();
2119 s->row = packet_get_int();
2120 s->col = packet_get_int();
2122 s->xpixel = packet_get_int();
2123 s->ypixel = packet_get_int();
2125 if (strcmp(s->term, "") == 0) {
2130 /* Allocate a pty and open it. */
2131 debug("Allocating pty.");
2132 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2138 error("session_pty_req: session %d alloc failed", s->self);
2141 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2143 /* for SSH1 the tty modes length is not given */
2145 n_bytes = packet_remaining();
2146 tty_parse_modes(s->ttyfd, &n_bytes);
2149 pty_setowner(s->pw, s->tty);
2151 /* Set window size from the packet. */
2152 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2155 session_proctitle(s);
2160 session_subsystem_req(Session *s)
2168 s->subsys = packet_get_string(&len);
2170 debug2("subsystem request for %.100s by user %s", s->subsys,
2173 for (i = 0; i < options.num_subsystems; i++) {
2174 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
2175 prog = options.subsystem_command[i];
2176 cmd = options.subsystem_args[i];
2177 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2178 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2179 debug("subsystem: %s", prog);
2181 if (stat(prog, &st) < 0)
2182 debug("subsystem: cannot stat %s: %s",
2183 prog, strerror(errno));
2184 s->is_subsystem = SUBSYSTEM_EXT;
2185 debug("subsystem: exec() %s", cmd);
2187 success = do_exec(s, cmd) == 0;
2193 logit("subsystem request for %.100s by user %s failed, "
2194 "subsystem not found", s->subsys, s->pw->pw_name);
2200 session_x11_req(Session *s)
2204 if (s->auth_proto != NULL || s->auth_data != NULL) {
2205 error("session_x11_req: session %d: "
2206 "x11 forwarding already active", s->self);
2209 s->single_connection = packet_get_char();
2210 s->auth_proto = packet_get_string(NULL);
2211 s->auth_data = packet_get_string(NULL);
2212 s->screen = packet_get_int();
2215 if (xauth_valid_string(s->auth_proto) &&
2216 xauth_valid_string(s->auth_data))
2217 success = session_setup_x11fwd(s);
2220 error("Invalid X11 forwarding data");
2223 free(s->auth_proto);
2225 s->auth_proto = NULL;
2226 s->auth_data = NULL;
2232 session_shell_req(Session *s)
2235 return do_exec(s, NULL) == 0;
2239 session_exec_req(Session *s)
2243 char *command = packet_get_string(&len);
2245 success = do_exec(s, command) == 0;
2251 session_break_req(Session *s)
2254 packet_get_int(); /* ignored */
2257 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2263 session_env_req(Session *s)
2266 u_int name_len, val_len, i;
2268 name = packet_get_cstring(&name_len);
2269 val = packet_get_cstring(&val_len);
2272 /* Don't set too many environment variables */
2273 if (s->num_env > 128) {
2274 debug2("Ignoring env request %s: too many env vars", name);
2278 for (i = 0; i < options.num_accept_env; i++) {
2279 if (match_pattern(name, options.accept_env[i])) {
2280 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2281 s->env = xreallocarray(s->env, s->num_env + 1,
2283 s->env[s->num_env].name = name;
2284 s->env[s->num_env].val = val;
2289 debug2("Ignoring env request %s: disallowed name", name);
2298 session_auth_agent_req(Session *s)
2300 static int called = 0;
2302 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2303 debug("session_auth_agent_req: no_agent_forwarding_flag");
2310 return auth_input_request_forwarding(s->pw);
2315 session_input_channel_req(Channel *c, const char *rtype)
2320 if ((s = session_by_channel(c->self)) == NULL) {
2321 logit("session_input_channel_req: no session %d req %.100s",
2325 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2328 * a session is in LARVAL state until a shell, a command
2329 * or a subsystem is executed
2331 if (c->type == SSH_CHANNEL_LARVAL) {
2332 if (strcmp(rtype, "shell") == 0) {
2333 success = session_shell_req(s);
2334 } else if (strcmp(rtype, "exec") == 0) {
2335 success = session_exec_req(s);
2336 } else if (strcmp(rtype, "pty-req") == 0) {
2337 success = session_pty_req(s);
2338 } else if (strcmp(rtype, "x11-req") == 0) {
2339 success = session_x11_req(s);
2340 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2341 success = session_auth_agent_req(s);
2342 } else if (strcmp(rtype, "subsystem") == 0) {
2343 success = session_subsystem_req(s);
2344 } else if (strcmp(rtype, "env") == 0) {
2345 success = session_env_req(s);
2348 if (strcmp(rtype, "window-change") == 0) {
2349 success = session_window_change_req(s);
2350 } else if (strcmp(rtype, "break") == 0) {
2351 success = session_break_req(s);
2358 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2362 fatal("session_set_fds: called for proto != 2.0");
2364 * now that have a child and a pipe to the child,
2365 * we can activate our channel and register the fd's
2367 if (s->chanid == -1)
2368 fatal("no channel for session %d", s->self);
2369 channel_set_fds(s->chanid,
2371 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2372 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2376 * Function to perform pty cleanup. Also called if we get aborted abnormally
2377 * (e.g., due to a dropped connection).
2380 session_pty_cleanup2(Session *s)
2383 error("session_pty_cleanup: no session");
2389 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2391 /* Record that the user has logged out. */
2393 record_logout(s->pid, s->tty, s->pw->pw_name);
2395 /* Release the pseudo-tty. */
2397 pty_release(s->tty);
2400 * Close the server side of the socket pairs. We must do this after
2401 * the pty cleanup, so that another process doesn't get this pty
2402 * while we're still cleaning up.
2404 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2405 error("close(s->ptymaster/%d): %s",
2406 s->ptymaster, strerror(errno));
2408 /* unlink pty from session */
2413 session_pty_cleanup(Session *s)
2415 PRIVSEP(session_pty_cleanup2(s));
2421 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2436 return "SIG@openssh.com";
2440 session_close_x11(int id)
2444 if ((c = channel_by_id(id)) == NULL) {
2445 debug("session_close_x11: x11 channel %d missing", id);
2447 /* Detach X11 listener */
2448 debug("session_close_x11: detach x11 channel %d", id);
2449 channel_cancel_cleanup(id);
2450 if (c->ostate != CHAN_OUTPUT_CLOSED)
2456 session_close_single_x11(int id, void *arg)
2461 debug3("session_close_single_x11: channel %d", id);
2462 channel_cancel_cleanup(id);
2463 if ((s = session_by_x11_channel(id)) == NULL)
2464 fatal("session_close_single_x11: no x11 channel %d", id);
2465 for (i = 0; s->x11_chanids[i] != -1; i++) {
2466 debug("session_close_single_x11: session %d: "
2467 "closing channel %d", s->self, s->x11_chanids[i]);
2469 * The channel "id" is already closing, but make sure we
2470 * close all of its siblings.
2472 if (s->x11_chanids[i] != id)
2473 session_close_x11(s->x11_chanids[i]);
2475 free(s->x11_chanids);
2476 s->x11_chanids = NULL;
2479 free(s->auth_proto);
2480 s->auth_proto = NULL;
2482 s->auth_data = NULL;
2483 free(s->auth_display);
2484 s->auth_display = NULL;
2488 session_exit_message(Session *s, int status)
2492 if ((c = channel_lookup(s->chanid)) == NULL)
2493 fatal("session_exit_message: session %d: no channel %d",
2494 s->self, s->chanid);
2495 debug("session_exit_message: session %d channel %d pid %ld",
2496 s->self, s->chanid, (long)s->pid);
2498 if (WIFEXITED(status)) {
2499 channel_request_start(s->chanid, "exit-status", 0);
2500 packet_put_int(WEXITSTATUS(status));
2502 } else if (WIFSIGNALED(status)) {
2503 channel_request_start(s->chanid, "exit-signal", 0);
2504 packet_put_cstring(sig2name(WTERMSIG(status)));
2506 packet_put_char(WCOREDUMP(status)? 1 : 0);
2507 #else /* WCOREDUMP */
2509 #endif /* WCOREDUMP */
2510 packet_put_cstring("");
2511 packet_put_cstring("");
2514 /* Some weird exit cause. Just exit. */
2515 packet_disconnect("wait returned status %04x.", status);
2518 /* disconnect channel */
2519 debug("session_exit_message: release channel %d", s->chanid);
2522 * Adjust cleanup callback attachment to send close messages when
2523 * the channel gets EOF. The session will be then be closed
2524 * by session_close_by_channel when the childs close their fds.
2526 channel_register_cleanup(c->self, session_close_by_channel, 1);
2529 * emulate a write failure with 'chan_write_failed', nobody will be
2530 * interested in data we write.
2531 * Note that we must not call 'chan_read_failed', since there could
2532 * be some more data waiting in the pipe.
2534 if (c->ostate != CHAN_OUTPUT_CLOSED)
2535 chan_write_failed(c);
2539 session_close(Session *s)
2543 verbose("Close session: user %s from %.200s port %d id %d",
2545 get_remote_ipaddr(),
2550 session_pty_cleanup(s);
2553 free(s->x11_chanids);
2554 free(s->auth_display);
2556 free(s->auth_proto);
2558 if (s->env != NULL) {
2559 for (i = 0; i < s->num_env; i++) {
2560 free(s->env[i].name);
2561 free(s->env[i].val);
2565 session_proctitle(s);
2566 session_unused(s->self);
2570 session_close_by_pid(pid_t pid, int status)
2572 Session *s = session_by_pid(pid);
2574 debug("session_close_by_pid: no session for pid %ld",
2578 if (s->chanid != -1)
2579 session_exit_message(s, status);
2581 session_pty_cleanup(s);
2586 * this is called when a channel dies before
2587 * the session 'child' itself dies
2590 session_close_by_channel(int id, void *arg)
2592 Session *s = session_by_channel(id);
2596 debug("session_close_by_channel: no session for id %d", id);
2599 debug("session_close_by_channel: channel %d child %ld",
2602 debug("session_close_by_channel: channel %d: has child", id);
2604 * delay detach of session, but release pty, since
2605 * the fd's to the child are already closed
2608 session_pty_cleanup(s);
2611 /* detach by removing callback */
2612 channel_cancel_cleanup(s->chanid);
2614 /* Close any X11 listeners associated with this session */
2615 if (s->x11_chanids != NULL) {
2616 for (i = 0; s->x11_chanids[i] != -1; i++) {
2617 session_close_x11(s->x11_chanids[i]);
2618 s->x11_chanids[i] = -1;
2627 session_destroy_all(void (*closefunc)(Session *))
2630 for (i = 0; i < sessions_nalloc; i++) {
2631 Session *s = &sessions[i];
2633 if (closefunc != NULL)
2642 session_tty_list(void)
2644 static char buf[1024];
2649 for (i = 0; i < sessions_nalloc; i++) {
2650 Session *s = &sessions[i];
2651 if (s->used && s->ttyfd != -1) {
2653 if (strncmp(s->tty, "/dev/", 5) != 0) {
2654 cp = strrchr(s->tty, '/');
2655 cp = (cp == NULL) ? s->tty : cp + 1;
2660 strlcat(buf, ",", sizeof buf);
2661 strlcat(buf, cp, sizeof buf);
2665 strlcpy(buf, "notty", sizeof buf);
2670 session_proctitle(Session *s)
2673 error("no user for session %d", s->self);
2675 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2679 session_setup_x11fwd(Session *s)
2682 char display[512], auth_display[512];
2683 char hostname[NI_MAXHOST];
2686 if (no_x11_forwarding_flag) {
2687 packet_send_debug("X11 forwarding disabled in user configuration file.");
2690 if (!options.x11_forwarding) {
2691 debug("X11 forwarding disabled in server configuration file.");
2694 if (options.xauth_location == NULL ||
2695 (stat(options.xauth_location, &st) == -1)) {
2696 packet_send_debug("No xauth program; cannot forward with spoofing.");
2699 if (options.use_login) {
2700 packet_send_debug("X11 forwarding disabled; "
2701 "not compatible with UseLogin=yes.");
2704 if (s->display != NULL) {
2705 debug("X11 display already set.");
2708 if (x11_create_display_inet(options.x11_display_offset,
2709 options.x11_use_localhost, s->single_connection,
2710 &s->display_number, &s->x11_chanids) == -1) {
2711 debug("x11_create_display_inet failed.");
2714 for (i = 0; s->x11_chanids[i] != -1; i++) {
2715 channel_register_cleanup(s->x11_chanids[i],
2716 session_close_single_x11, 0);
2719 /* Set up a suitable value for the DISPLAY variable. */
2720 if (gethostname(hostname, sizeof(hostname)) < 0)
2721 fatal("gethostname: %.100s", strerror(errno));
2723 * auth_display must be used as the displayname when the
2724 * authorization entry is added with xauth(1). This will be
2725 * different than the DISPLAY string for localhost displays.
2727 if (options.x11_use_localhost) {
2728 snprintf(display, sizeof display, "localhost:%u.%u",
2729 s->display_number, s->screen);
2730 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2731 s->display_number, s->screen);
2732 s->display = xstrdup(display);
2733 s->auth_display = xstrdup(auth_display);
2735 #ifdef IPADDR_IN_DISPLAY
2737 struct in_addr my_addr;
2739 he = gethostbyname(hostname);
2741 error("Can't get IP address for X11 DISPLAY.");
2742 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2745 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2746 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2747 s->display_number, s->screen);
2749 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2750 s->display_number, s->screen);
2752 s->display = xstrdup(display);
2753 s->auth_display = xstrdup(display);
2760 do_authenticated2(Authctxt *authctxt)
2762 server_loop2(authctxt);
2766 do_cleanup(Authctxt *authctxt)
2768 static int called = 0;
2770 debug("do_cleanup");
2772 /* no cleanup if we're in the child for login shell */
2776 /* avoid double cleanup */
2781 if (authctxt == NULL)
2785 if (options.use_pam) {
2787 sshpam_thread_cleanup();
2791 if (!authctxt->authenticated)
2795 if (options.kerberos_ticket_cleanup &&
2797 krb5_cleanup_proc(authctxt);
2801 if (compat20 && options.gss_cleanup_creds)
2802 ssh_gssapi_cleanup_creds();
2805 /* remove agent socket */
2806 auth_sock_cleanup_proc(authctxt->pw);
2809 * Cleanup ptys/utmp only if privsep is disabled,
2810 * or if running in monitor.
2812 if (!use_privsep || mm_is_monitor())
2813 session_destroy_all(session_pty_cleanup2);